Small rectangular dampers or doors are used in air passages of automobile heaters and air conditioner units to change the direction of air flow from floor heat to upper vents, from interior air to outside air, to defrost position and the like. These dampers are usually mounted on rods which project from opposite sides to provide pivotal mounting for the dampers.
These damper or door plates have, in recent years, been metal plates covered with a foam plastic sheet on one or both sides to reduce the noise of opening and closing and to provide a built in seal at the edges when the damper is moved from one position to another.
In an effort to reduce the weight in the smaller and lighter cars, there has been a move to plastic panels to be substituted for the base metal substrates. These panels have been molded individually but the molds are expensive and the process time consuming because of the cooling period needed for each plate as it comes from the mold.
Another difficulty with some of these dampers has been the need to apply certain support shafts after positioning the panel in the proper operative location. In some cases, it is necessary to attach the pivot rods after this positioning. This has been done with the application of a self-tapping screw inserted and tightened by one operator. In view of the tight space problems, this assembly is difficult and if done carelessly can lead to great difficulties after a heater is installed in a vehicle. Some snap-in devices requiring lateral pressure on the plate have been proposed but these are also difficult to achieve successfully in the confined space.
The present invention relates to a damper plate and a method of forming and assembly which accomplishes the objective of lighter weight, is adapted to simple multiple production, and is very easily and securely fastened in place.
Briefly, the invention consists of applying the foam sheeting on each side of a large panel sheet of plastic such as a substrate formed of polypropylene, ABS or the like. The sheet is then die cut, using steel rule dies, into a plurality of identical damper panels. Two tab slits are simultaneously cut into the panel at an edge or elsewhere. The tabs are thermoformed to provide snap-in recesses for spaced portions of a shaft, a perforation is provided between and below these recesses, and a button to socket a central loop in the shaft is pressed into the perforation to lock the shaft against movement.
The foam sheeting is compressed as the button is snapped in to provide a resilient and snug fit for the entire assembly.
Thus, a very inexpensive panel is provided with a secure fastening which is easily manipulated by the installer in a simple operation which he can see and feel with assurance of successful contact in each case.
Other objects and features of the invention will be apparent in the following description and claims in which the invention is set forth together with details directed to persons skilled in the art to enable successful practice of the invention, all in connection with the best mode presently contemplated for the invention.